Nearly a million US children potentially misdiagnosed with ADHD, study finds

Nearly one million children in the USA are potentially misdiagnosed with attention-deficit hyperactivity disorder simply because they are the youngest - and most immature - in their kindergarten class, according to new research by a Michigan State University economist.

These children are significantly more likely than their older classmates to be prescribed behavior-modifying stimulants such as Ritalin (methylphenidate), said Todd Elder, whose study will appear in a forthcoming issue of the Journal of Health Economics.

$320-$500 million unnecessary cost